Introduction: Installing Threaded Inserts in to Plywood

Picture of Installing Threaded Inserts in to Plywood

Threaded inserts are a great way to be able to secure something to a wood base.

The problem is, the manufacturer specifically states that installing these inserts in to plywood is not recommended. Since plywood is layers of thin wood glued together, it does not have the same strength as solid wood. But if you have a plywood base, what can you do?

This instructable will show you how to install a threaded insert in to plywood but still have the strength of solid wood. Also note, that this is being done on a piece of scrap plywood for testing purposes only. I have an upcoming project where I expect to be installing about 15 or so of these inserts. The base wood is plywood, so I wanted to see if there was a way to get the strength of solid wood while still being able to use the more cost effective plywood.

Again, this is strictly for testing purposes and I am not sure if this is even the best solution for my\your needs. I'm looking forward to any comments that may improve on this.

Step 1: Drill and Install Insert in to Your Plywood Base.

Picture of Drill and Install Insert in to Your Plywood Base.

I decided to test installing one of these inserts in to my plywood base. You can skip this step if you know you want to install the insert in to solid wood

A. Drill the appropriate hole for the insert you will be using.

B. Install the threaded insert

C. Test if insert is straight. Install a screw or bolt and see if it straight.

D. Test if screw and insert work to secure your item.

So it looks like this will work, but I'm concerned about long term. Over time, the device I secure with this insert may vibrate it loose and cause other issue. So let's see about getting the insert in to solid wood.

Step 2: Cut Out a Piece of Solid Wood

Picture of Cut Out a Piece of Solid Wood

I cut a 2" piece from a 1"x2" piece of pine. For some reason I didn't take pictures of tracing the piece of wood around the space I wanted to install the insert, but the original hole is directly in the middle of the piece of wood. I chose to put tape around it so I could more easily see the border as I am routering it out.

Step 3: Router Out a Spot for the Wood.

Picture of Router Out a Spot for the Wood.

Router out a spot big enogh to fit the piece of wood. Keep checking that the wood fits in to the routered space and that the depth is OK. If the solid wood is a little higher than the plywood, that is OK, it can be sanded down.

Step 4: Glue in to Place

Picture of Glue in to Place

Glue the solid wood in to the routered hole and let dry. Once you put the solid wood in, use some glue to help fill the gaps. Ultimately you will probably want to use actual wood filler to get a better look.

If you do plan on filling the gaps with wood filler and sanding everything smooth, do that now. You won't want to do it once to installed the threaded insert I will be painting the future project, so I would do that after sanding everything smooth.

Step 5: Drill Hole in to Solid Wood

Picture of Drill Hole in to Solid Wood

Drill the correct size hole for your insert in to the solid wood and install the insert. You now have a threaded insert installed in to solid wood, but supporting your plywood base.

Step 6: Comparison

Picture of Comparison

This last image is just a comparison of the threaded insert being installed in to the plywood and in to the solid wood.

Comments

garrydelf (author)2016-11-23

There are a couple of pieces of information missing in this article. You do not go into the correct method for installing this type of insert. Your photo seems to show the insert being installed with a driver made for the purpose but many of the people reading this will not have one and won't care to buy one. There are several instruction videos on You Tube that shows the installation of this type insert incorrectly. The slots on the insert are NOT for installing the insert with a screwdriver. This is a common mistake. They are to assist with cutting the threads into the wood and are inserted into the hole first. The correct method to install these inserts is to use a bolt and a nut of the same size as the internal thread of the insert. Thread the nut onto the bolt, run the bolt into the insert to the end of the threads in the insert, snug the nut up against the head of the insert and use a wrench on the nut to drive the insert in flush with the surface of the wood, hold the head of the bolt and loosen the nut then back out the bolt and you're done. Running the bolt to the end of the threads prevents stretching and deforming the threads in the insert. Sorry to be so long winded but I wanted to save people the frustration of trying to install an insert only to get it about half way in and have the slot strip out and wonder what to do next. Been there, done that, don't want to do it again!

tytower (author)2016-10-20

I would give you just a couple more suggestions . First is drill a much larger hole right through ,drill from both sides to stop splintering and use a backing piece if necessary to stop tearout . Cut a piece of appropriately sized dowel and glue it in with epoxy or polyurethane glue (not PVA) Put your insert into this .

Alternatively drill and insert thread as above but glue it in place . Plywoods weakness is its edges ut glueing it in seals the edges . I get the best results with epoxy and microballons mix and sand down and paint.

rsmaudsley (author)tytower2016-10-21

I've thought about putting glue in to the hole just before screwing in the insert. I can't drill all the way through because the bottom of the bench will actually be a side wall that is exposed to the elements when the bench is closed.

BeachsideHank (author)2016-10-18

These devices were originally designed to be used in particleboard type products, allowing for a high strength machine thread fastener to be used in assembly of cabinets, this also included plywood and other manmade products as well as some plastics, so I do not see why the manufacturer would caution against their use in the above. Although a t-nut is preferred for this type of duty, it is not always an option and these inserts handily filled a need.

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